they form the aperture at that end of the case. The larva then 

 crawls down to the base and finally completes the case by biting 

 through first one and then the other cuticle, thus cutting it com- 

 pletely away from the leaf. It then, bearing its case, walks off in 

 well-deserved triumph, though the way in which the newly acquired 

 habitation flops about borders on the ridiculous. 



The larva now soon finds a suitable spot on the under side of a 

 leaf where it can fasten its little case and bore into the leaf. Here 

 it recommences to feed in the usual coleophorid manner. As the 

 larva increases in size the case becomes too small to contain it 

 comfortably, so the larva increases the size of the case, for C. 

 fuscedinella does not at this period form another fresh case, as 1 

 believe C. grypliipennella does. The case is enlarged in two ways : 

 When the larva, having fastened its case to the leaf, has mined all 

 round to a convenient distance, it loosens the case from the leaf and 

 moves to a fresh place. In freeing the case it does not* sever the 

 silk strands by which the case was attached, but cuts a ring out of 

 the leaf cuticle, thus freeing the case and adding to it at the same 

 time. So that, after the larva has mined in three or four different 

 places, the case will have been prolonged by the attachment of 

 three or four rings, composed of silk and leaf cuticle, to its basal 

 aperture. 



At the same time the larva increases the width or depth of the 

 case by spinning a silk border along the ventral and apical margins 

 of its dwelling. After eight or ten weeks the original first case will 

 appear as a black patch on the back and sides of the now enlarged 

 case, but, unless examined carefully, it will be difficult to see where 

 the piece of leaf which formed the first case ends and the added 

 silken portion begins. 



The case at this period has some superficial resemblance, but ot 

 course in microscopical miniature, to the bivalve mollusc, Mya 

 tri/iicafa, in its living state, when the epidermis is still on the shell 

 and the wrinkled tube which encases the syphons is still attached. 



The larva now prepares for hibernation. It crawls off the leaves, 

 seemingly being aware that if it remained on them it would fall with 

 them to the earth. It now attaches its case by the basal aperture 

 very firmly to the bark of a tree of the food-plant. The site fre- 

 quently chosen is the angle formed by the stem of a twig and the 

 next year's leaf-bud. In this situation it braves the autumnal gales 

 and the winter's cold without any further protection. 



In the early spring, when the leaves are still very small, the larva 

 loosens its case from the bark and recommences to feed. It still 

 continues enlarging its case by rings of cuticle and silk as previously 

 described, but the silk and the rings now added are of a much lighter 

 colour, and, after a few weeks, the old winter case, which has now 

 become almost black, contiasts strongly with the pale additions of 

 the spring. When the leaves of the food-plant, be it birch, horn- 

 beam, or hazel, have grown sufficiently large, and when the leaf 



